Fabrication of Si(1-x)Ge(x) Alloy on Silicon by Ge-ion-implantation and Short-Time-Annealing


Fabrication of Si(1-x)Ge(x) Alloy on Silicon by Ge-ion-implantation and Short-Time-Annealing

Gao, K.; Prucnal, S.; Mücklich, A.; Skorupa, W.; Zhou, S.

Silicon-Germanium is commonly used as a semiconductor material in integrated circuits (ICs) for heterojunction bipolar transistors or as a strain-inducing layer for CMOS transistors. Normally epitaxial methods (e.g., CVD, MBE) are applied to the synthesis of Si1-xGex alloys.
In our contribution we present the fabrication of Si1-xGex alloy by ion-implantation and short-time-annealing. The Ge ions in the fluence range of 3×1016 - 10×1016 cm2 were implanted into monocrystalline (100)-oriented Si wafers covered by 50 nm thermal oxide at an energy of 100 keV. As the consequence, the 50 nm amorphous Ge rich Si layers were obtained. The recrystallization of the implanted layers and the Si1-xGex alloying were carried out by flash lamp annealing or scanning continuous laser annealing in the time scale of 20 ms or 1 s, respectively. Both flash lamp treatment and laser annealing at high energy densities lead to local melting of the germanium rich silicon layer. The recrystallization of the Si1-xGex layer takes place due to millisecond range liquid phase epitaxy. Formation of the high quality monocrystalline Si1-xGex layer was confirmed by μ-Raman spectroscopy, RBS channeling and cross-section TEM investigation. The μ-Raman spectra reveal tree phonon modes located at around 293, 404 and 432 cm-1 corresponding to the Ge-Ge, Si-Ge and Si-Si in the Si1-xGex alloy vibrational modes, respectively. Due to much higher carrier mobility in SiGe layer than in silicon such system can be used for the fabrication of advanced devices.

Keywords: Silicon Germanium; ion-implantation; flash lamp annealing; continuous laser annealing

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  • Lecture (Conference)
    IX-th International Conference Ion Implantation and other Applications of Ions and Electrons, 25.-28.06.2012, Kazimierz Dolny, Poland

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